Section R. 299.4441 - Type II landfill groundwater monitoring; assessment monitoring programRule 441.
(1) Assessment monitoring is required at a type II landfill if a statistically significant increase over background has been detected for 1 or more of the constituents listed in R 299.4440.(2) Within 60 days of the submittal of an assessment monitoring program, and annually thereafter, the owner and operator of a type II landfill shall sample the groundwater for analysis of all constituents listed in R 299.4450 to R 299.4452 and 40 C.F.R part 258, appendix II at an appropriate subset of monitoring wells approved by the director. A minimum of 1 sample from each approved downgradient well shall be collected and analyzed during each sampling event. For any constituent that is detected in the downgradient wells as a result of the complete R 299.4450 to R 299.4452 and appendix II constituent analysis, a minimum of 4 independent samples from each background and downgradient well shall be collected and analyzed to establish background for the constituents. The director shall consider anappropriate subset of wells to be sampled and analyzed for R 299.4450 to R 299.4452 and appendix II constituents during assessment monitoring. The director shall delete any of the R 299.4450 to R 299.4452 and appendix II constituents for a unit if it can be shown, based on leachate data, secondary collection system monitoring, waste classification data, or other data, that the removed constituents are not reasonably expected to be in or derived from the waste contained in the unit or that the constituent is not a reliable indicator parameter.(3) The director shall specify an appropriate frequency for repeated sampling and analysis for all of the R 299.4450 to R 299.4452 and appendix II constituents for which sampling and analysis are required by this rule during the active life, including closure, and post-closure care of the unit. In specifying the frequency, the director shall consider all of the following factors: (a) The lithology of the aquifer and unsaturated zone.(b) The hydraulic conductivity of the aquifer and unsaturated zone.(c) Groundwater flow rates.(d) The minimum distance between upgradient edge of the unit and downgradient monitoring well screen.(e) The nature of any constituents detected in response to this rule.(4) After obtaining the results from the initial or subsequent sampling events required in subrule (2) of this rule, the owner and operator shall do all of the following: (a) Within 14 days, place a notice in the operating record that identifies the R 299.4450 to R 299.4452 and appendix II constituents that have been detected and notify the director that this notice has been placed in the operating record.(b) Within 90 days, and on at least a semiannual basis thereafter, resample all wells specified by the provisions of R 299.4441(2), conduct analyses for all constituents listed in R 299.4450 to R 299.4454 and for those constituents listed in appendix II that are detected in response to the requirements of subrule (2) of this rule and are present at statistically significant levels above background, and record their concentrations in the facility operating record. At least 1 sample from each background and downgradient well shall be collected and analyzed during these sampling events. The director shall consider an alternative monitoring frequency during the active life, including closure, and the post-closure period for the constituents referred to in this subdivision. The alternative frequency for constituents listed in R 299.4452 to R 299.4454, during the active life, including closure, shall be at least annually. The alternative frequency shall be based on consideration of the factors specified in subrule (3) of this rule.(c) Establish background concentrations for any constituents detected pursuant to this rule where background has not already been established.(d) Establish groundwater protection standards consistent with section 20120a of the act for all constituents that are detected pursuant to this rule.(5) If the concentrations of all constituents listed in R 299.4450 to R 299.4454 and all appendix II constituents are shown to be at or below background values, using the statistical procedures in R 299.4908, for 2 consecutive sampling events, then the owner and operator shall notify the director of the finding and may return to detection monitoring.(6) If the concentration of any constituent listed in R 299.4450 to R 299.4454 or any appendix II constituents are above background values, but all concentrations are below the groundwater protection standard established pursuant to the provisions of subrule (9) of this rule, then the owner and operator shall do all of the following:(a) Continue assessment monitoring in accordance with this rule.(b) Characterize the nature and extent of the release by installing additional monitoring wells as necessary.(c) Install at least 1 additional monitoring well at the facility boundary in the direction of contaminant migration and sample the well in accordance with the provisions of subrule (4) of this rule.(d) Notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site as indicated by the sampling of wells in accordance with this rule.(7) If 1 or more constituent listed in R 299.4450 to R 299.4454 or appendix II constituents are detected at statistically significant levels and are above the groundwater protection standard established pursuant to subrule (9) of this rule, in any sampling event, then the owner or operator shall do all of the following: (a) Within 14 days of the detection, place a notice in the operating record that identifies the hazardous substances that have exceeded any criteria for groundwater established pursuant to section 20120a of the act.(b) Notify the director and all appropriate local government officials that the notice has been placed in the operating record.(c) Continue assessment monitoring in accordance with this rule.(d) Install at least 1 additional monitoring well at the facility boundary in the direction of contaminant migration and sample the well in accordance with subrule (4) of this rule.(e) Characterize the nature and extent of the release by installing additional monitoring wells as necessary.(f) Notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site as indicated by the sampling of wells in accordance with this rule.(g) Except as provided by subrule (8) of this rule, initiate an assessment of corrective measures as required by R 299.4443 within 90 days of the detection.(8) An owner and operator may demonstrate that a source other than a type II landfill unit or other source at the facility caused the contamination or that the statistically significant increase resulted from error in sampling, analysis, or statistical evaluation or from natural variation in groundwater quality. A report that documents the demonstration shall be certified by a qualified groundwater scientist, approved by the director, and placed in the operating record. Until a successful demonstration is made, the owner and operator shall comply with subrules (6) and (7) of this rule. If a successful demonstration is made, the owner and operator shall do the following:(a) Continue monitoring in accordance with the assessment monitoring program pursuant to this rule. The owner and operator may return to detection monitoring if the hazardous substances are at or below background as specified in subrule (5) of this rule.(b) Determine whether any new units or lateral extensions of existing units will be unmonitorable. If so, the owner and operator shall develop a schedule for submitting revised engineering plans for such lateral extensions and new units that are in compliance with the provisions of R 299.4422(4), and include a leak detection system.(c) Not be subject to the response action plan requirements of R 299.4442 or the assessment of corrective measures of R 299.4443.(9) The owner or operator shall establish a groundwater protection standard for each hazardous substance that is detected in groundwater. The groundwater protection standard shall be as follows: (a) For constituents for which a maximum contaminant level has been promulgated pursuant to the provisions of section 1412 of the safe drinking water act and has been codified at 40 C.F.R. part 141, the lowest of the following:(i) The maximum contaminant level for that constituent.(ii) The applicable cleanup criteria for that constituent for groundwater as established pursuant to section 20120a of the act.(b) For constituents for which the background level is higher than the maximum contaminant level or applicable cleanup criteria for groundwater, the background concentration.(c) For constituents for which a maximum contaminant level has not been promulgated, either of the following:(i) The background concentration for the constituent established from wells in accordance with the provisions of R 299.4906(1).(ii) The applicable cleanup criteria for that constituent for groundwater established pursuant to section 20120a of the act.Mich. Admin. Code R. 299.4441